Aircraft



March 16,19 7. w A. P. BRUSH 2,073,864

' AIRCRAFT I Filed Nov. 10, 1934 2 Sheets-Sheet 2 I E i 5 lNVENT O R(7242750)? F BY 1 ATTORNEYS.

tented 16, 1937 This invention relates to aircraft and particularlytosuch aircraft as are equipped with pontoom permitting them to land uponand take oil from a body oi water, the principal object being a theprovision of a pontoon structure for aircraft that is simple inconstruction and efficient in operation.

obiecm of the invention include the provision of a, pontoon structurefor aircraft that will exert lo a minimum amount of drag to passage overor re lease from a water surface; the provision of an A aircraft pontoonthat will have an equal hydrodynamic lift for each increment of itslength and.

width when passing over the water and thereby it will aid in preventingpitching of the cooperating airplane; the provision of a pontoon forairplanes so constructed and arranged as to haveta planing surface ofmaterial width and length so asto provide a relatively great amount ofstability 20 therein hutin which the dimensions of the planing surfacetaken in any vertical plane parallel with the longitudinal ams oi theairplane will be relatively small so as to provide a minimum ofresulting drag when in contact with the water;

25 the provision of an airplane pontoon so 0011- structed and arrangedthat all portions of the planing surfaces thereof when planing upon awater surface will not be required to pass over water which has beenpreviously disturbed by '30 another or other portions of a planingsurface;

the provision of an airplane pontoon of V shape in plan and of airfoilsection in a vertical plane taken parallel to the axis of the airplaneand so constructed and arranged that the lower sur- 335 face thereofwill serve as a. planing surface when in contact with the water; theprovision ofa pontoon structure for airplanes of sucha construction asto offer a minimum amount of'hydrodynamic and aerodynamic drag and amaximum 4o amount of hydrodynamic and aerodynamic lift;

and the provision of a'pontoon structure'for airplanes so constructedand arranged that its buoyant eflect when moving on the water will bematerially greater than its buoyant effect when at rest 46 on the water.

' Other. bjects include the provision of an airplanehaving a novel armor pontoon structure associated therewith; the provision of an airplane-having a pontoon structure so constructed and 50 arranged as toaerodynamically react upon the air through which it is passingso. as tocause such reaction with the airto substantially support a.

material amount of the weight thereof; the provision ofan airplanehaving a pontoon structure 55 associated therewith so constructed andarm, 1934, Se No. man

(on. era-ms) Y with the pontoon adjusted for flight conditions.

' ranged so as to cause a minimum amount of vertical movement of theairplahe and a minimum amount of pounding of the pontoon on the waterwhen passing over relatively rough water; and the provision of anairplane having a pontoon strucl5 ture of airfoil section associatedtherewith and so adjustable in inclination with respect to the path oftravel as to permit the pontoon to be adjusted for optimum water contactconditions and optimum flight conditions. 7

The alcove being among the objects of the present invention, the sameconsists in certain novel features of construction and combinations ofparts to be herelnafter'described with reference to the/accompayingdrawin and then claimed, having the above and other objects in view.

In the accompanying drawings which illustrate a suitable embodiment ofthe present invention and [in which like numerals refer to like partsthroughout the several difierent views,

Fig. l is a partially broken side elevational view of snail-planeequipped with my improved pontoon structm'e, and shown at rest upon awater surface.v

Fig. 2 is a front elevational view-of the-con-' structlon shown in Fig.1.

Fig. 3 is e. slightly reduced side elevatlonal view of the airplaneshown in Fig. 1 during flight and Fig. 4 is an enlarged {sectional viewtaken on the line il-t of Fig. 1 showing the float in plan view. 1

Fig. 5 is anenlarged vertical sectional view taken on the line 5-5 ofFig. 4.

It is common practice to fix to the underside of airplanes buoyantbodies commonly known as pontoons to enabl'e the airplane to land uponor 1 take ofl' from a body of water. Insome cases a.

single pontoon is employed and made of sumcient width to provide thenecessary lateral stability, while in other cases two laterally spacedpon toons are employed each of relatively narrow width aInd the spacingof which provides the necessary lateral stability for the airplane onwater. .In bothcases the pontoons are made,of

sufllcient length to obtain the necessary longitudinal stability. Ineither case it is usually the practice to form the underside ofthepontoon to conform to the general practice of shaping the bottoms ofhydroplanes so that when the airplane is passing over'a body of waterand supportedor partially. supported on the water the reaction betweenthe water and.the'pontoons will tend to raise the pontoon; out 01 thewater and i5 to permit them to slide over the surface thereof. Due tothe shape of such planing surfaces, they create a considerable amount ofdrag caused by adhesion of the water and such surfaces which must beovercome when the airplane is lifting to bring the pontoons out ofcontact with the water, and in a great many instances where the surfaceof the water is substantially smooth, unless it is possible tomomentarily relieve this drag by artificially roughening the surface ofthe water, it is impossible, particularly where the airplane isrelatively heavily loaded, to get it off of the water. After airplanesequipped with such pontoons are once in the air it will be apparent thatthe pontoons themselves, which must be relatively heavily constructed inorder to withstand the usages to which they are put when in contact withthe water, and because they have little 1 or no aerodynamic value, forma substantially dead weight which must be supported by the airplane inaddition to its load and such pontoons, accordingly, considerably reduceboth the. pay load andthe factor of safety of the airplane. Also as suchpontoons are conventionally constructed they provide a considerablygreater amount of buoyancy than that actually required .to support theairplane on the water when at rest and are conventionally of such shapethat if the airplane is running on the water and the water is rough thevariations in lifting effect on the pontoons caused by the waves causesthe pontoons to be heavily pounded by the water and subjects theairplane 'to relatively violent vertical forces fostering earlydestruction of the same and tending to cause pitching of the airplane.All of these disadvantages of conventional constructions are, to a greatmeasure, overcome by the present invention.

Referring now to the accompanying drawings, in Fig. 1 is illustrated anairplane illustrated as of the low wing monoplane type' including afuselage l0, wings ll, cowl l2 enclosing an engine, not shown, whichdrives a tractor propeller l4, and other usual and/or conventionalparts. Mounted below the airplane is a pontoon struc ture indicatedgenerally in Figs. 1 to 3, inclusive, at l6. A pair of laterally spacedsupports l8,

preferably of airfoil section, are fixed to the wings I l and projectdownwardly therefrom, their lower ends being connected by pins 20 andbrackets 22 with the forward portion of the pontoon l6. .Braces 23 arepreferably provided between the lower ends of the supports l8 and thefuselage It! to impart added rigidity to the supports.

- While any suitable means may be provided for securing the rear end ofthe pontoon llito the fuselage III, that shown by way of illustrationcomprises a link 24 pivotally connected at its lower end to the rearportion of the pontoon i6 and pivotally connected at its upper end toone arm of a bell crank 26 pivotally mounted on the fuselage at 28. Theotherarm of the bell crank 26 is connected by a rod 30 to a lever 32pivoted to the fuselage at 34. Suitable locking means including a sector36 and manually. controllable latch member 38 is provided for releasablylocking the lever 32 in pivotally adjusted position.

As will be apparent, movement of the lever 32 acting through the links24 and 30 and bell crank 26 will cause the-rear end of the pontoon IE tobe raised or lowered according to the direction of movement of the lever32 and thus vary the inclination of the pontoon with respect to thecentral aiiis of the airplane.

Referring now to Figs. 4 and 5. it will be noted preferance and by wayof illustration, as opening toward the front of the airplane. ,Therearwardly converging sides 40 of the pontoon are of a material width asindicated and the crosssectional configuration of the pontoon is suchthat a section of the same taken substantially .any vertical planeparallel to the longitudinal axis of the airplane at any point in thelength or width of the pontoon is of airfoil section as indicated inFig. 5. In other words, such view will indicate that the pontoon isprovided with a relatively blunt leading edge 42, a relatively sharptrailing edge 44, a relatively flat lower face 45 and a generally curvedor rounded upper face l8 which generally simulates the section of athick sectioned airplane wing.

For the purposes of the present invention it is preferable that when thegeneral plane of the pontoon is parallel to the longitudinal axis of theairplane the angle of the lower face 46 measured-in a vertical planeparallel to the section taken in Fig. 5 will be inclined upwardly andforwardly so that it will be sufficient for proper planing reaction uponthe water when the airplane is running over the surface of the water inlanding or in preparation to taking off. In other words, the angle ofattack of'the pontoon is preferably greater than the angle of attack ofthe wings ll under such circumstances. In this respect it will beunderstood, of course, that the airplane, in order to obtain maximumspeed upon the water and when wholly or partially supported on the waterby the pontoon, will be positioned with its longitudinal axis preferablyparallel with the surface of the water or slightly inclined upwardly andforwardly therefrom. When the airplane is at rest, however, its nose ispreferably slightly elevated with respect to its tail and, accordingly.it is preferable to so position the pontoon It with respect to theairplane that the center of buoyancy of the pontoon which is illustratedat 50 in Fig. 4 is preferably disposed rear wardly of a vertica'llineindicated at 52 in Fig. 4 passing through the-center of mass of theairplane. Thus when the airplane is at rest upon the water it willassume the relative position with respect to the surface of the water 56indicated in Fig. 1. It will be understood, of course, that as soon asthe airplane is put under way while supported by the water the reactionof the water against the lower surface 46 of the pontoon will providethe principal source of support for the airplane on the water, andbecausethe pontoon is designed for simultaneous water contact at alltimes over its full length and width the airplane will substantiallyimmediately assume a position in which its longitudinal axis issubstantially parallel to the general plane of the pontoon l6 under suchconditions. Another feature of the present invention in this respect isillustrated in Fig. 5

. wherein is illustrated the condition which occurs when the airplane isfirst put in motion while supported on the water and in which it will benoted that, due to the forward movement of the pontoon I 6 in the water,the relative flow of water under the trailing edge 44 will cause atrough of ontact the full length of the surface 46 as measured in avertical plane parallelto the longi 'tudinal axis of the airplane, andas the speedof the airplane increases this length of water contact withthe surface 66 will decrease in proportion to the increase in speed.Thus by the time aspeed sumcient to take off from the wat r is reachedonly a very small amount of water contact, measured in the mannerreferred to above,

will remain and-very little, if any, efiort will be required to break itloose from the water when the rudder is elevated to take ofi.

'As will particularly be noted-from an inspec- This, coupled with thefact that the pontoon is of airfoil section in the direction of movement7 and presents a relatively small bulk to the water, will lessen thepitching of the airplane when the water is rough and while at rest.Additionally,

2 when the water is rough and the airplane is runhim; on the water thissame feature will permit the pontoon to break completely'through waveswith but relatively small variations in the buoyant lifting efiect ofthe pontoons on the airplane and consequently will reduce pitching ofthe airplane under such conditions and will relieve both the pontoonsand the airplane of considerable stress which would otherwise occur dueto such pitching caused from variations in the buoyant 35 lifting efiectof the pontoons. Additionally, be-

cause of the ll-like formation of the pontoons,

only a relatively small area thereof will come at y disposed below thesame, said pontoon being of once into contact with the waves as thepontoon is passing over the water, but rather each increment of lengthwill successively come in contact with the waves. and will thuseliminate to a great extent the pounding which occurs in conventional-constructions due to a relatively broad surface instantaneouslyreceiving the full force 45 of a wave which is met. These factors willaid in providing a pontoon structure eliminating many -of the moreserious defects of conventional constructions. a I Because ofthe-airfoil section of the pontoon, it will be apparent that not onlydoes it provide a suitable planing surface when the airplane is runningover the water but additionally after the airplane has taken 01f fromthe water the very nature of the shape of the pontoon will cause it toserve as an additionarairfoilor lifting sur': face of the airplane, andthe ivariation of this lifting effect may be controlled by operating thelever 38 so as to raise orlower the rear end of the pontoon iii tocontrol the angularity of the m other words, its angle bf attack.Ordinarily, because of the preferred angularity of the lower surface ofthe airfoil section of the pontoon for use when planing over the water,it will be desirable to raise the rear end of the pontoon. when in theair to a position such as indicated in Fig. 3, so 'as to bringthe'ch'ord of the airfoil section thereof into substantial parallelismwith the chordof the main wingsJ I, or to equalize the angles of attackof their surfaces, In such position it will be apparent that with apontoonconstruction of suitable lightness the lifting effect on theponchord of theairfoil section of the pontoon with'. respect to thedirection of travel of the airplane,

' toon by the air may be suflicientto support a sub- 1 gtantial if notthe entire weight of the pontoon and thus relieve the airplane itself ofthis additional load during flight. In fact with proper designandmaterials the pontoon may be capable of not only supporting its weightthrough its aerodynamic action on the air; but also serve as an addedlifting surface for the airplane as a whole,

1 aiding in supporting the loadthereof. ,In this respect it will-benoted that, because of the characteristics of the present pontoon aspreviously pointed out in connection with its action on and in thewater, it does not require as heavy-a construction as is necessitated inconventional constructions. The structural features of the pontoon are,however, immaterialiasfar as the present invention is concerned as longas the proper shape and contour thereof is substantially maintained andany suitable type or form of construction and material may be employedin the same.

. Formal changes may be made in the specific embodiment of the inventiondescribed without departing from the spirit or substance of the broadinvention, the scope of which is commensurate with the appended claims.

What I claim is:

1. In combination, an airplane, a relatively fiat pontoon of flI-shapedformation in plan view with the opening of the v disposed toward thefront of the airplane mounted below the same, the bottorn surface ofsaid pontoon on each side of said V being approximately planular andformed to providea positive hydrodynamic angle with re.- j

spect to the general plane of the pontoon and means for varying thegeneral plane of the pon- -toon with respect to the longitudinal axis ofthe airplane during flight.

2. In combination, an airplane and appntoon l-shaped formation in planview with the opening of the v disposed toward the front of the air-'plane and of a shape presenting an airfoil section when viewed insubstantially any vertical plane 3. A pontoon for airplanes andthe likecom--- prising a relatively fiat buoyant body of V-shaped formation inplan view and of airfoil shape in a vertical section taken parallel withthe longitudinal axis of the pontoon, the opening of the V beingdisposed toward the front of the pontoon the angle of attack of said"airfoil section being positive with respect to the general plane of saidpontoon' and the bottom line of any suclr section being substantially.flat whereby toprovide a water planing surface at an angle to thegeneral plane of the pontoon.

4. In combination, an' airplane, a pontoon secured'to the under-sidethereof, said pontoon being of V-shaped formation in plan view with theopening of the V disposed toward the'front of the airplane and ofairfoil shape in any section takenbetween its lateralside'edges in a.vertical plane arranged at a positive and material angle with respect tothe plane of said trailing edges whereby to provide a hydrodynamicplaning surface having a positive planing angle, and 'means for varyingthe position of said pontoon relative to said central axis whereby theangle of incidence of said sections with respect to said central axismay be varied in flight.

5. In combination, an airplane, a pontoon structure mounted therebelow,said structure having pontoon portions extending at an angle to a.vertical plane through the longitudinal axis of the airplane, saidportions being spaced apart a great-- er distance at the front than atthe rear and being of airfoil section in planes parallel to saidvertical plane, the rear portions of the bottom lines of said sectionsbeing substantially straight and disposed at a material positive planingangle to the general horizontal plane of said pontoon structure, andmeans for varying the angle of attack of the pontoon during flight.

6. In combination, an airplane and a pontoon disposed below the same,said pontoon being of V-shaped formation in plan view with the openingof the V disposed toward the front of the airplane, v

said pontoon being of a shape presenting an airfoil section when viewedin substantially any vertical plane taken throughout its width andparall'el to the longitudinal axis 01. the airplane, the rear portion ofthe bottom line of any such section being substantially flat to form aplaning surface and being disposed at a material positive planing angleto the plane of the trailing edge of said pontoon.

ALANSON P. BRUSH.

